<template>
  <div class="goods">
    <div class="menu-wrapper" ref="menuWrapper">
      <ul>
        <li
          v-for="(item, index) in goods"
          :key="index"
          class="menu-item"
          :class="{'current':currentIndex===index}"
          @click="selectMenu(index, $event)"
        >
          <span class="text border-1px">
            <span v-show="item.type>0" class="icon" :class="classMap[item.type]"></span>
            {{item.name}}
          </span>
        </li>
      </ul>
    </div>
    <div class="foods-wrapper" ref="foodsWrapper">
      <ul>
        <li v-for="(item, index) in goods" class="food-list food-list-hook" :key="index">
          <h1 class="title">{{item.name}}</h1>
          <ul>
            <li
              @click="selectFood(food, $event)"
              v-for="(food, index) in item.foods"
              class="food-item border-1px"
              :key="index"
            >
              <div class="icon">
                <img :src="food.icon" width="57" height="57">
              </div>
              <div class="content">
                <h2 class="name">{{food.name}}</h2>
                <p class="desc">{{food.description}}</p>
                <div class="extra">
                  <span class="count">月售{{food.sellCount}}份</span>
                  <span>好评率{{food.rating}}%</span>
                </div>
                <div class="price">
                  <span class="now">￥{{food.price}}</span>
                  <span class="old" v-show="food.oldPrice">￥{{food.oldPrice}}</span>
                </div>
                <div class="cartcontrol-wrapper">
                  <cartcontrol :food="food" @cardAdd="_drop"></cartcontrol>
                </div>
              </div>
            </li>
          </ul>
        </li>
      </ul>
    </div>
    <shopcart
      ref="shopcart"
      :select-foods="selectFoods"
      :delivery-price="seller.deliveryPrice"
      :min-price="seller.minPrice"
    ></shopcart>
    <food :food="selectedFood" ref="food" @cardAdd="_drop"></food>
  </div>
</template>

<script type="text/ecmascript-6">
import BScroll from 'better-scroll';
import shopcart from 'components/shopcart/shopcart';
import cartcontrol from 'components/cartcontrol/cartcontrol';
import food from 'components/food/food';

const ERR_OK = 0;
export default {
  props: {
    seller: {
      type: Object
    }
  },
  data () {
    return {
      goods: [],
      listHeight: [],
      scrollY: 0,
      selectedFood: {}
    };
  },
  computed: {
    currentIndex () {
      for (let i = 0; i < this.listHeight.length; i++) {
        let height1 = this.listHeight[i];
        let height2 = this.listHeight[i + 1];
        if (!height2 || (this.scrollY >= height1 && this.scrollY < height2)) {
          return i;
        }
      }
      return 0;
    },
    selectFoods () {
      let foods = [];
      this.goods.forEach(good => {
        good.foods.forEach(food => {
          if (food.count) {
            foods.push(food);
          }
        });
      });
      return foods;
    }
  },
  created () {
    this.classMap = ['decrease', 'discount', 'special', 'invoice', 'guarantee'];
    this.$http.get('/api/goods').then(res => {
      res = res.body;
      if (res.errno === ERR_OK) {
        this.goods = res.data;
        this.$nextTick(() => {
          this._initScroll();
          this._calculateHeight();
        });
      }
    });
  },
  methods: {
    selectMenu (index, event) {
      if (!event._constructed) {
        return;
      }
      let foodList = this.$refs.foodsWrapper.getElementsByClassName(
        'food-list-hook'
      );
      let el = foodList[index];
      this.foodsScroll.scrollToElement(el, 300);
    },
    selectFood (food, event) {
      if (!event._constructed) {
        return;
      }
      this.selectedFood = food;
      this.$refs.food.show();
    },
    _initScroll () {
      this.menuScroll = new BScroll(this.$refs.menuWrapper, {
        click: true
      });
      this.foodsScroll = new BScroll(this.$refs.foodsWrapper, {
        // 当 probeType 为 1 的时候，会非实时（屏幕滑动超过一定时间后）派发scroll 事件；
        // 当 probeType 为 2 的时候，会在屏幕滑动的过程中实时的派发 scroll 事件；
        // 当 probeType 为 3 的时候，不仅在屏幕滑动的过程中，而且在 momentum 滚动动画运行过程中实时派发 scroll 事件。
        // 如果没有设置该值，其默认值为 0，即不派发 scroll 事件
        click: true,
        probeType: 3
      });
      this.foodsScroll.on('scroll', pos => {
        this.scrollY = Math.abs(Math.round(pos.y));
      });
    },
    _calculateHeight () {
      let foodList = this.$refs.foodsWrapper.getElementsByClassName(
        'food-list-hook'
      );
      let height = 0;
      this.listHeight.push(height);
      for (let i = 0; i < foodList.length; i++) {
        let item = foodList[i];
        height += item.clientHeight;
        this.listHeight.push(height);
      }
    },
    _drop (target) {
      // 用户体验优化，异步执行下落动画
      console.log('_drop');
      this.$nextTick(() => {
        this.$refs.shopcart.drop(target);
      });
    }
  },
  components: {
    shopcart,
    cartcontrol,
    food
  }
};
</script>

<style lang="stylus" rel="stylesheet/stylus">
@import '../../common/stylus/mixin.styl'

.goods
  display: flex
  position: absolute
  top: 174px
  bottom: 46px
  width: 100%
  overflow: hidden
  .menu-wrapper
    flex: 0 0 80px
    width: 80px
    background: #f3f5f7
    .menu-item
      display: table
      height: 54px
      width: 56px
      line-height: 14px
      padding: 0 12px
      &.current
        position: relative
        z-index: 10
        margin-top: -1px
        background: #fff
        font-weight: 700
        .text
          border-none()
      .icon
        display: inline-block
        vertical-align: top
        width: 12px
        height: 12px
        margin-right: 2px
        background-size: 12px 12px
        background-repeat: no-repeat
        &.decrease
          bg-image('decrease_3')
        &.discount
          bg-image('discount_3')
        &.guarantee
          bg-image('guarantee_3')
        &.invoice
          bg-image('invoice_3')
        &.special
          bg-image('special_3')
      .text
        display: table-cell
        width: 56px
        vertical-align: middle
        border-1px(rgba(7, 17, 27, 0.1))
        font-size: 12px
  .foods-wrapper
    flex: 1
    .title
      padding-left: 14px
      height: 26px
      line-height: 26px
      border-left: 2px solid #d9dde1
      font-size: 12px
      color: rgb(147, 153, 159)
      background: #f3f5f7
    .food-item
      display: flex
      margin: 18px
      padding-bottom: 18px
      border-1px(rgba(7, 17, 27, 0.1))
      &:last-child
        border-none()
        margin-bottom: 0
      .icon
        flex: 0 0 57px
        margin-right: 10px
      .content
        flex: 1
        .name
          margin: 2px 0 8px 0
          height: 14px
          line-height: 14px
          font-size: 14px
          color: rgb(7, 17, 27)
        .desc, .extra
          line-height: 10px
          font-size: 10px
          color: rgb(147, 153, 159)
        .desc
          margin-bottom: 8px
          line-height: 12px
        .extra
          .count
            margin-right: 12px
        .price
          font-weight: 700
          line-height: 24px
          .now
            margin-right: 8px
            font-size: 14px
            color: rgb(240, 20, 20)
          .old
            text-decoration: line-through
            font-size: 10px
            color: rgb(147, 153, 159)
        .cartcontrol-wrapper
          position: absolute
          right: 0
          bottom: 12px
</style>
